I have r-1ed it quite a few times, almost all of the time it was around 400ish, the highest was around 500.
The problem with the higher flows is getting under the bridges up top, at 500 I portaged the bridge at the dream house, the land owners were super cool.
I always portage the top drop of four falls and the top of super max, I do put in and run tampax. The crux of super max is just a little to sketchy for my taste, it looks like it can go in a raft but the fuck up factor is high.
I usually run into more problems in the steep section just below four falls the more water the pushier and tighter lines.
Also I have run into some interesting issues below deer creek with various pieces of wood.
My advice is if you go, no more than an r-3, if kayakers are with you run last this way you do not block the only line.
Be very heads up for wood.